A method for the production of low pressure gaseous oxygen includes providing a system of distillation columns and a heat exchanger, wherein the system of columns comprises a lower pressure column, a higher pressure column, an auxiliary column, the auxiliary column having a distillation section, a first reboiler, and a second reboiler, wherein the LP column and the HP column are thermally integrated via a top reboiler/condenser disposed on top of the HP column. A cooled air stream is rectified within the system of columns such that the auxiliary column produces a cold oxygen fluid that is then warmed in the heat exchanger to produce a low pressure oxygen product. The cooled air stream provides reboiling duty for the first reboiler prior to rectification within the system of columns, and a compressed nitrogen stream received from a cold end of the heat exchanger provides reboiling duty for the second reboiler.

The invention relates to a plant for low-temperature air separation, having a rectification column system comprising a high-pressure column, a divided low-pressure column and a divided argon column, and a cold box system comprising a first cold box and a second cold box. The high-pressure column is arranged beneath the lower section of the low-pressure column. The high-pressure column together with the lower section of the low-pressure column is located in the first cold box, and the top section of the low-pressure column in the second cold box. It is proposed to arrange the base section of the argon column in the first cold box and the top section of the argon column in the second cold box, or vice versa. The present invention likewise provides a corresponding method.

The invention relates to a plant for low-temperature fractionation of air, having a rectification column system comprising a high-pressure column, a divided low-pressure column and an argon column, and a coldbox system comprising a first coldbox, a second coldbox and a third coldbox. The high-pressure column is disposed beneath the lower section of the low-pressure column. The high-pressure column together with the lower portion of the low-pressure column is disposed in the first coldbox, and the top portion of the low-pressure column in the second coldbox. It is proposed that the argon column or one or more sections of the argon column be disposed in the third coldbox. The pure oxygen column is disposed in the second coldbox. The present invention likewise provides a corresponding process.

A method for separating air is provided, in which a flow of oxygen-rich liquid is sent to a top of a pure oxygen column, having a pure oxygen reboiler, in which said flow is purified in order to form a vessel liquid containing at least 98 mol % of oxygen and the vessel liquid is drawn off as a product. A supercharged airflow at a second pressure is sent to the pure oxygen reboiler and to a liquid oxygen vaporizer; a nitrogen-rich gas is drawn from the top of the medium-pressure column and sent to an intermediate reboiler of the low-pressure column and the condensed gas is sent to the top of the medium-pressure column; and a nitrogen-rich gas or air is sent to a vessel reboiler of the low-pressure column and the liquid that condenses therein is sent to the medium-pressure column.

A method for the cryogenic separation of air, in which method an air separation plant with a rectification column arrangement is used, which plant has a pressure column, a low-pressure column, a raw argon column and pure argon column. In the method, evaporation gas from a head gas condensation device associated with the raw argon column is partially or completely fed into the low-pressure column in a first feed-in region, whereas evaporation gas from a head gas condensation device associated with the pure argon column and excess liquid from this head gas condensation device are partially or completely fed into the low-pressure column in a shared second feed-in region. In one embodiment, flash gas forming during the expansion of cooling fluid into the head gas condensation device associated with the raw argon column can be partially or completely fed into the low-pressure column in the second feed-in region.

An apparatus for the production of low pressure gaseous oxygen includes a heat exchanger and a system of columns comprised of an auxiliary column, a higher pressure column and a lower pressure column. The LP column and the HP column are thermally integrated via a top reboiler/condenser disposed on top of the HP column. The system of columns is configured to separate a cooled air stream into oxygen and nitrogen. The auxiliary column comprises a distillation section and a first and second reboiler. One of the reboilers is driven by the cooled air stream and the other reboiler is driven by a pressurized nitrogen stream. The first and second reboilers boil their fluids at the same pressure as the auxiliary column.

A method for the production of low pressure gaseous oxygen includes providing a system of distillation columns and a heat exchanger, wherein the system of columns comprises a lower pressure column, a higher pressure column, an auxiliary column, the auxiliary column having a distillation section, a first reboiler, and a second reboiler, wherein the LP column and the HP column are thermally integrated via a top reboiler/condenser disposed on top of the HP column. A cooled air stream is rectified within the system of columns such that the auxiliary column produces a cold oxygen fluid that is then warmed in the heat exchanger to produce a low pressure oxygen product. The cooled air stream provides reboiling duty for the first reboiler prior to rectification within the system of columns, and a compressed nitrogen stream received from a cold end of the heat exchanger provides reboiling duty for the second reboiler.

A process for recovering at least one fluid (e.g. argon gas and/or nitrogen gas, etc.) from a feed gas (e.g. air) can provide an improved recovery of argon and/or nitrogen as well as an improvement in operational efficiency. Some embodiments can be adapted so that at least a portion of a mixed nitrogen-oxygen fluid is at least partially vaporized and fed to a low pressure column.

A process for cryogenic fractionation of air uses an air fractionation plant (100-400) comprises a rectification column system (10) having a high-pressure column (11) operated at a pressure level of 9 to 14.5 bar, a low-pressure column (12) operated at a pressure level of 2 to 5 bar, and an argon column (13). A recirculating stream is formed using a second top gas or a portion thereof, which is heated, compressed, cooled again, and after partial or complete liquefaction or in the unliquefied state is introduced partially or completely, or in fractions, into the first rectification column (11) and/or into the second rectification column (12).

A device for separating air by cryogenic distillation, comprising a first module containing a main air compressor, a second module, a third module containing a purification unit, a fourth module containing a heat exchanger and a system of columns comprising at least one distillation column that is or is not contained in the fifth module, the second module containing a connection for connecting the compressor of the first module to the purification unit of the third module in order to send compressed air from the compressor to the purification unit and also containing a connection for connecting the purification unit to the heat exchanger of the fourth module in order to send purified air in the purification unit to the heat exchanger.